commit 5e311d32e4079bf7f2db001d4f08db3ac0d93af9
Author: Panu Matilainen <pmatilai@redhat.com>
Date:   Fri Aug 11 12:48:23 2017 +0300

    Really ignore unknown signature tags (RhBug:1480407)
    
    Rather embarrassingly, rpm 4.13 fails rpmkeys -K signature verification
    of rpm 4.14 packages because it doesn't really ignore unknown
    signature tags like it claims to, and should. And so it reports a
    bogus failure on the new SHA256 header-only digest. This bug as it is
    only exists in 4.13.x, older versions are fine and >= 4.14 only
    ever looks for tags it knows about.

diff --git a/lib/signature.c b/lib/signature.c
index 1b9fe345f..41bf85893 100644
--- a/lib/signature.c
+++ b/lib/signature.c
@@ -71,6 +71,7 @@ rpmRC rpmSigInfoParse(rpmtd td, const char *origin,
 	break;
     default:
 	/* anything unknown just falls through for now */
+	sinfo->type = RPMSIG_OTHER_TYPE;
 	break;
     }